Working hardened steel ??

I have some projects comming up I will be making stuff from scrap auto parts.

Axles from rear wheel drive cars would be good for some parts, but how would I turn them or mill them?
Can I used normal bits and cutters, or will I need to heat the shafts and soften them before machining. Then heat treat them again to harden when done?

When I buy new cutters, end mills and such, what is the best type to get for longest life amd using on hardend steel, cast iron, spring steel and such.

Where can I find a chart or guide on spark testing to see what I am working. I know the principle of spark testing, but really I wouldn't know a red flower from a silver sparkler as far as what metal I have.

Some projects planed, metal former for rolling beads and flanges (I figure axle shafts would be good here), Draw knife (perhaps from auto coil spring) this would be more blacksmithed then sharpened. Other similar stuff.

Thanks.

Attempting to make parts from automotive scrap will generally cost you $50 to $100 in trashed tooling for every $1 in material savings. Stuff like this is the absolute epitome of mystery metals and is guaranteed to provide nothing but frustration in trying to make useful parts.

I use "mystery metal" all the time and can tell you that metlmunchr is giving you GOOD ADVISE!

Some material problems are not due to hardness but toughness; for lack of a better term. This sometimes makes getting a good surface finish very difficult.

As far as hardness, I use an old mill file to test. This method is not conclusive but I get a pretty good idea of whether I can cut it or not.

I routinely cut preharded 4130 with high speed steel cutters. It is supposed to be in the low 30's on the Rockwell "C" scale.

Those axle shafts are probably hardened on the ends but may cut easily in the center.

Maybe some of the more experienced guys will have more helpful advise.

Rick

This sounds like my kind of project.

Rear axles are case hard....I have used High speed...but prefer carbide insert cutter.
I have cut right through axles with a bi-metal blade band saw. Axles are not going to be your problem. Re-hardening them....thats a trick.
Go with case hardening them again...If you need hard through to the core good luck. (mystery metal is right!)

Auto springs? Yuk....I have cut them in half with a torch. They aren't very good metal. I don't think I would use them as a blade.

Tooling recomenedations. I always use carbide (fine grade) when I can get it. Run it at the right speeds/feeds will last forever.

Good Luck!
Thanks BT

If you want to make some nice parts, buy some nice material. If you want to waste time and goof off, auto scrap will let you learn what material NOT to use.

John

Put a point on a car axle and they make great tent stakes. I've got to get another truck axle to a buddy of mine to get it forged into another 5' pry bar. I've seen guys weld a head on a leaf spring, put a handle on it and use as a tree planting pick. Seemed to work OK. I've seen truck crankshafts used as mail box stands. Axle housings used as jack stands. But best was a small box chevy used as a planter.

Those are the only things that used car parts are realy good for IMO.
JR

Repower;
if you are convinced that you want to use this material do this.

get some large chunks of wood or go to your local sawmill and get lots of the scrap they would normally throw away and in a SAFE area make a stack using a good 6" to 8" of wood on the bottom.
then put the axels you wish to use on the base you have just built leave 4" to 6" open between the axels then build another 1' of wood on top of the axels.

set fire to this and make sure its burning evenly all around.

keep an eye on it and when its rendered down let it continue to sit for 3 days.

at this point it will be annealed and dead soft.

then you can machine it all you want...jim

Leaf springs can be cut and ground into nice shapes for form tools if you were making say chess
figures or ornamental shapes.

.....I've used automotive steel for may non-critical (meaning if it broke no one dies) things. For the most part it has all worked well. This is non-production home, hobby, fun type stuff. The material has been free or very cheap.

A set of reloading dies and shellholder made from the 7/8" hard chromed strut rods from an '86 Chevy Celebrity. Had to use carbide to cut the threads, but all internal cutting was with HSS and it produced a superb finish.


What I call an 'Intermediate Collet' made from some strut rod. I have 5C's x32nds and one was too large, the next too small to grip the part, so I made this to take up the slop.


A couple punches made from a tie rod and used as swage punches to alter Berdan primer pockets to large rifle size. Heated and used Kasenite and they are HAAAAAARD!

Rick

Just here to agree with Metlmuncher and Johnoder,
If you are going to spend money on new tooling,
why destroy it on mystery metal? On rare
times I do use mystery metal I attack it
with a tool from my dull carbide tooling drawer
to see what I am up against. There are plenty of
nice shaft type steels that are easy to machine,
respond well to heat treating, and not too expensive to waste time and tooling trying to
machine things out of junk.

work hardening, i may be confused a bit.

i know that there are 2 means of hardening brass:
1. heat
2. impact (hit it with a hammer, it will harden)

off the point - manganese steel will harden by heat, for example if you drill into it, the friction heat will increase the hardening, therefore making any future drilling dificult ( if you pause during drilling).

could you rate me on this quick & prompt reply please?
regards, mike

could you rate me on this quick & prompt reply please?

Click to expand...

Sorry Mike, but I'm afraid you only get about a 5 or 6 tonite The action you describe on manganese steels is classic work hardening and not thermal hardening. The surface is made harder by the high pressure rubbing action of the drill on the material. To harden a steel via thermal means requires that the steel be heated to about 1450*F, or more, depending on the particular steel. This is well past red and into the yellow heat range. While it would be possible to generate temperatures in this range via drilling, the drill wouldn't look like a drill anymore. It would be more of a molten blob on the cutting end. We hired a fabricator (his description of himself, not mine) one time whose specialty was making drills into blobs like this, and he was so efficient at it that he only needed mild steel to ply his craft

Seriously, its ironic that you mention manganese steels, since there are certain manganese bearing steels, used primarily in rock crushers, that have such a high tendency toward work hardening that they are classified as essentially impossible to machine. No heat required. Just the force of the tool against the material, under a flood of coolant, immediately work hardens the surface such that the tool, steel or carbide, simply cannot cut the material. When you consider that the rocks it crushes have the same effect on the material, you get a better idea of just why crusher parts will last as long as they do. If the material didn't work harden, the parts would likely be worn thru in a matter of hours.

Back on scrap auto steels, did you know that there is a big cottage industy in Nepaul.
Many of the blades for the famous KUKRI Ghurker knives are fashioned from discarded leaf springs.
A fair bit of time is spent on the smith's anvil and the result is a good, durable tool (weapon).

Railroad "frogs" (the point of the switch that takes all the rubbing from wheel flanges going by) were always made from cast manganese steel for the reasons metlmuncher states.

John

GAWD!!! Track frogs!! I had to machine a couple of pair right from the maker. Boy are they tough. I used a big rugged double box column planer-mill conversion with honking big 30 HP Futuremil heads with 9" dia Quills. The machine shivered and shook like a monkey $hittin' peach seeds. I bet that job ate three boxes of carbide inserts by the time I tortured off 1/4 and got lousy finishes.

The track boss told me not to worry. The big cranes would mash out the ugly part in no time. And they did.

Thanks for all the replies, and thanks Buckshot for those great pics an ideas. I want a reloader for my 303 shells, never thought of making my own and can't justify buying one, don't shoot enough, but if shells were cheaper I proabably would I geuss

A few reasons I do want to use mystery metal as it's been reffed to

I don't really have any decent metal sellers nearby, in other words I would probably have to order and wait for stuff as needed. Most of my projects won't be planned out very well, I think of them at night and want to cut in morning (or durring a sleepless night). Auto junk is handy right in the yard, or if I don't have it, like an axle shaft, I can get it about 7AM right down the road. Also cost, auto scrap is cheap/free as well.
Most of my stuff will be hobby stuff I make for only me so I can't stock alot of steels in various sizes/shapes new just to have it around, don't have the money.
For many things I may order the right new metals of course, and if doing work for others and being paid I would for sure. But general hobby stuff and tools I may use 1 or 2 times here and there I'd use what's on hand if I can.

Like the rollers for a metal former I thought of. I bought the unit from Harbor Freight, rolls beads in sheet metal, $200 normal got it $100 on sale. Pretty sure the China steel it's made from probably ain't the best to begin with, so any extra shapers I make for it will probably be better than it came with. I want some other size bead rollers it does not have. If I can turn a rear wheel drive axle shaft on my lathe then I can make the rollers I want free. I will probably use them for about a month if they work and then maybe a couple times a year after that. The sheet metal I plan to roll beads in is pannels cut from cars and vans also, so not the thickest or best of metals either. Roofs, hoods, door skins, etc.. About anything with a 2'x2' or larger area of rust free sheet metal.

I'll take most of the advice, and test some metals to see how they work, then try to seperate into piles depending what they are and came from.